OR, A TREATISE ON PILE. 37 
Fourcoy first remarked that a liair, when rolled between the fingers, always passes from 
the button to the apex; this he attributed to the presence of scales, which had not then 
been seen.* Mr. Youatt first saw these scales upon wool, and Dr. Goring first saw them 
upon the hair of the head of man. So far as we know, Prof. Dungleson is the only one 
in the United States, (except ourselves,) who has seen these hair scales. 
Of the Scales.—The study of the scales is very interesting in a scientific point of view ; 
and, since it has been demonstrated, that on wool they are the main cause of the felting 
and fulling property, they have become still more so in an economical one. 
Figure 2 represents these scales as they are found upon hair and wool; and figure 42 
shows a portion of the cortex that has no scales, but is paved ; these ought to be examined 
and compared by those who wish to understand the nature of the cortex. 
Of the Uses of the Scales on Pile to the Animal.—lIt is probable that the scales on the 
cortex of pile, by polarizing the rays of light, may contribute to the variation in the color 
or shade of the coats of some of the lower animals. By their form and number they are 
nicely adapted to admit to the interior of the filament just as much air and moisture as is 
necessary for the growth of pile, excluding the remainder which might prove injurious. In 
this latter respect they may be to the cortex what stomate are to the cuticle of plants ; 
and, like them, they may be endowed with the power of opening and closing, according 
to circumstances ; but we acknowledge that we have not been able to detect such a 
motion.+ 
Ribbons of scaly cortex may be artificially separated from the body of the pile, to be 
viewed as transparent objects under the microscope. Figure 43 represents one of these 
from the spine of the pecary. 
The scales may be detached from the cortex by concentrated sulphuric acid. 
The cortex is sometimes the seat of the coloring matter, as will be explained under 
that head. 
Of the Paved Cortez.—We use this word “ paved,” in the description of this variety of 
cortex upon the authority of Prof. Dungleson, who, in describing Epithelium, introduces 
the words, “ paved and tesselated.”’ (See p. 108 of Hum. Phys., fig. 23.) We prefer the 
word ‘“ paved,” because “ tesselated,”’ from its derivation, might imply that the divisions 
are all squares, whereas some of them are pentagons, hexagons and polygons. They are 
not scales—do not lap one over the other ; but are mere divisions of the cortex, into angular 
portions like a paved or tesselated floor. See fig. 44, for an illustration. 
Examples of the Paved Cortex.—(See. fig. 34.)—In the order ‘“ Ruminantia,’ in the 
Section “‘ Horned,” the Tribe “ Solid and deciduous horns,” is found one single genus, the 
“* Stag,” (Cervus,) which is divided into five species, viz:— 
* This experiment may be best repeated by rolling two hairs between the fingers in opposite directions. 
+ Roget, (in his Anat. Veg. Physi., 1 v., p. 68,) says that it is evident from the functions the stomate perform, that they 
must occasionally open and close; but the minuteness of their size precludes any accurate observation as to the nature of the 
apparatus, &e. 
